The present invention relates to a pneumatic tire including a packed puncture sealant layer and a method of manufacturing the same.
In the laid-open Japanese patent application No. 8-323875, a method of making a tire which has a sealing fluid layer for self-sealing tread punctures has been proposed, wherein the tire is provided inside the tread with a bag-like portion which is flat during making and vulcanizing the tire, but after the tire is vulcanized, filled with an injected sealing fluid. This bag-like portion is an unbonded part between the carcass and the inner liner formed by applying talc (a release agent for the tire and mold) thereto to prevent them from bonding together.
In this method, however, it is difficult to stably form the bag-like portion with accuracy. If the applied talc is insufficient, unbonded part is not formed. Thus, the talc tends to be applied more than enough. As a result, there is a possibility that the bonding between the inner liner and the carcass becomes partially insufficient.
It is therefore, an object of the present invention to provide a pneumatic tire and a manufacturing method therefor, in which a bag-like portion into which a self-sealing material is injected can be formed stably with accuracy without lowering the production efficiency.
According to one aspect of the present invention, a pneumatic tire comprises
a tread portion,
an annular anti-adhesive sheet embedded in the tread portion along the inside of the tire, the annular anti-adhesive sheet made of a material which does not firmly adhere to adjacent rubber so as to form a bag-like portion as an unbonded part extending continuously in the tire circumferential direction,
the bag-like portion filled with a self-sealing material for self-sealing punctures, and
the anti-adhesive sheet having circumferential ends being spliced, and in the spliced portion, at least one of the circumferential ends disposed radially inwards of the other circumferential end having an edge inclined at an angle of from 30 to 60 degrees with respect to the widthwise direction of the anti-adhesive sheet.
According to another aspect of the present invention, a method of manufacturing the pneumatic tire comprises the steps of: building a green tire, which includes a step of embedding the anti-adhesive sheet; vulcanizing the green tire; and injecting the self-sealing material into the bag-like portion after the tire is vulcanized.